Ensure that GC idle notifications either make progress or stop requesting more GCs.

test/unittests/heap/gc-idle-time-handler-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 
 #include "src/heap/gc-idle-time-handler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
@@ skipping 447 matching lines @@
   }
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
   // Emulate mutator work.
   for (int i = 0; i < GCIdleTimeHandler::kIdleScavengeThreshold; i++) {
     handler()->NotifyScavenge();
   }
   action = handler()->Compute(0, heap_state);
   EXPECT_EQ(DO_NOTHING, action.type);
 }
 
+
+TEST_F(GCIdleTimeHandlerTest, KeepDoingDoNothingWithZeroIdleTime) {
+  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerIdleRound;
+       i++) {
+    GCIdleTimeAction action = handler()->Compute(0, heap_state);
+    EXPECT_EQ(DO_NOTHING, action.type);
+  }
+  // Should still return DO_NOTHING if we have been given 0 deadline yet.
+  GCIdleTimeAction action = handler()->Compute(0, heap_state);
+  EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, DoneIfNotMakingProgressOnSweeping) {
+  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+
+  // Simulate sweeping being in-progress but not complete.
+  heap_state.incremental_marking_stopped = true;
+  heap_state.can_start_incremental_marking = false;
+  heap_state.sweeping_in_progress = true;
+  heap_state.sweeping_completed = false;
+  double idle_time_ms = 10.0;
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerIdleRound;
+       i++) {
+    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+    EXPECT_EQ(DO_NOTHING, action.type);
+  }
+  // We should return DONE after not making progress for some time.
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DONE, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, DoneIfNotMakingProgressOnIncrementalMarking) {
+  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+
+  // Simulate incremental marking stopped and not eligible to start.
+  heap_state.incremental_marking_stopped = true;
+  heap_state.can_start_incremental_marking = false;
+  double idle_time_ms = 10.0;
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerIdleRound;
+       i++) {
+    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+    EXPECT_EQ(DO_NOTHING, action.type);
+  }
+  // We should return DONE after not making progress for some time.
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DONE, action.type);
+}
+
 }  // namespace internal
 }  // namespace v8